Very slow directory traversal

[Ross Boylan]

On Sat, 2007-10-06 at 12:06 +0100, Alex Bligh wrote:
> 
> --On 06 October 2007 00:10 -0700 Ross Boylan <ross at biostat.ucsf.edu> wrote:
> 
> > I believe I created it this way; in particular, I'm pretty sure I've had
> > dir_index from the start.
> 
>   find /var/spool/cyrus -type d -exec lsattr -lad \{\} \;
> 
> and check the large directories are actually indexed
> 
> Alex
All the large directories are indexed, but some smaller or empty ones
seem not to be.  Here's a line from the directory I reported on, and
then one that doesn't show as indexed.  The find took about 3 minutes to
run.
/var/spool/cyrus/mail/r/user/ross/debian/user Indexed_direcctory
/var/spool/cyrus/mail/r/user/ross/debian/devel ---

During the find, as during my other operations that take a long time,
vmstat shows around 40-45% of the CPU time in io wait.  I'm not sure if
the pseudo-dual CPU's are throwing that off, i.e., if that really means
80-90%.